Land locked by mountains and sea, Alaska's residents can only access their state capital by plane or by the Alaska Marine Highway System. This in turn makes Juneau, the capital of the largest US state, a de-facto island city in terms of transportation. All goods come in or out only by plane or boat, in spite of the city being located on the Alaskan mainland. A lot of tourists still come to Alaska and its capital every year to enjoy the incredible views of this region. By the way, the area of Juneau is even bigger than that of the smallest US state, Rhode Island!

More Info: en.wikipedia.org